Rotary actuator



3, 1963 s. KONGELBECK 3, ,902

ROTARY ACTUATOR Filed April 8, 1959 3 Sheets-Sheet 1 HYDRAULIC SUPPLY FIG.2

SVERRE KONGELBECK INVENTOR.

wg w 601W ROL SIG/VAL AT TORNEYS SERVO AMPLIFIER Dec. 3, 1963 s. KONGELBECK 3,112,902

ROTARY ACTUATOR Filed April 8, 1959 5 Sheets-Sheet 2 I4 FIG .3

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ATTORNEYS Dec. 3, 1963 s. KONGELBECK ROTARY ACTUATOR 3 Sheets-Sheet 3 Filed April 8, 1959 SVERRE KONGELBECK INVENTOR.

ATTORNEYS United States Patent 3,112,902 ROTARY ACTUATOR Sverre Kongelbeck, Silver Spring, Md, assignor to the United States of America as represented by the Secretary of the Navy Filed Apr. 8, 1959, Ser. No. 805,108 6 Claims. (Cl. 244-14) The present invention relates generally to hydraulic actuators. More particularly it relates to an improved Wing or fin actuator for use with guided missiles and other aerial vehicles.

An important object of the invention is to provide a hydraulic rotary actuator which will be compact and capable of installation as a complete unitary package.

Another object of the invention resides in the provision of an actuator which is directly coupled to the shaft of the fin or wing to be moved, thus eliminating the need for cylinder mount, piston and crank, with their attendant flexure.

A further object of the invention is to provide a relatively short fluid column from a servo valve to an actuator, thus reducing system elasticity which would be present with cylinder and linkage arrangements and structural compliance.

Still another object of the invention is to provide an actuator for high temperature application which utilizes no internal packing or moving seals resulting in longer shelf life.

An additional object of the invention is to provide an actuator which will produce no thrust on the shaft of the fin or wing.

Still an additional object of the invention resides in the provision of a rotary actuator for moving a fin by applying a uniform torque to the shaft of the fin throughout its motion.

Another object of the invention contemplates the coupling of a potentiometer directly with an actuator which eliminates any linkage from the fin and permits adjustment of the potentiometer from the outside of the miss-ile.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in [connection with the accompanying drawings, wherein:

FIG. 1 is a plan view showing the top of the improved actuator with a fragment of a fin of an aerial vehicle;

FIG. 2. is a cross sectional view showing the improved actuator in an aerial vehicle with only a small fragment of the vehicle and fin being illustrated taken on line 22 of FIG. 1;

FIG. 3 is a side elevation of the actuator within the aerial vehicle body casting;

FIG. 4 is a cross sectional view of the actuator taken on line 44 of FIG. 3; and

FIG. 5 is an exploded perspective View of the actuator.

Referring more particularly to the drawings, a portion of the body casting of an aerial vehicle is shown at and a relatively thick-walled hub or boattail casting at 11 with a central cylindrical opening. Formed in the upper end of the hub 11 is a recess 12.

The actuator of the present invention includes a stator sleeve or cylinder 13 which has an integral mounting plate 14 at its upper end. The mounting plate 14 is mounted in the recess r12 and secured to the hub by bolts 54 with the sleeve 13 fitting within the central opening of the hub '11. Grooves 15m are formed in the outer wall of the sleeve 13 to receive sealing rings 16 for providing a fluid-tight seal between the sleeve 13 and the hub 11.

Grooves 15b formed between grooves 15a are for conveying hydraulic fluid.

Mounted in the upper and lower end portions of the stator sleeve 13, by pins 17, are stator elements 18 and 19. These elements 18 and 19 are best seen in FIGS. 2 and 5. Each of the elements 18 and 19 have grooves 20 and sealing rings 21 for providing fluid seals. By referring to FIG. 5, it will be seen that the stator element 19 includes a ring 19a and four stator members 19b integral with said ring. The lower end of the stator ring has a reduced portion for receiving a retaining nut 40. The stator members 1% have a keystone contour and are equally spaced about the upper end face of the ring. The configuration of the stator element 18 is similar with that of the element 19. Element 1 8 has a ring 18a with the lower end face having four stator members 1817 of keystone shape equally spaced apart and in alignment with the stator members 19b. The work ing faces 18c and 18d of stator members 18b and working faces 19c and 19d of stator members 19b have chamfered edges on the outer surface of the keystone configuration.

The stator sleeve 13 is provided with sets of spaced bores 22a. and 22b (FIGS. 3, 4 and 5). The bores 22a extend from upper groove 15b to the chamfered edge of the working face 18c of stator members 18b. The set of bores 22b extend through the sleeve from lower groove 15b to the chamfered edge of the working face 19d of stator members 19]). The sleeve 13 is also provided near its outer end with a threaded course 23 (FIG. 5) for receiving a retaining nut 40.

The numeral 24 indicates generally a control surface, such as a fin or wing, of a missile or other aerial vehicle. The fin 24 includes a hollow stub shaft 25 and an enlarged portion 26 formed with an annular groove 27. The shaft 25 is fixed to a rotor sleeve 28 to rotate therewith, by a key 29 fitting keyway 2% on the shaft, (FIGS. 2, 4 and 5). The rotor sleeve is mounted within the stator sleeve 13 and has a rotor 30 fixed thereon, as by pins 31.

The structure of the rotor 30 is best illustrated in FIGS. 2 and 5, said rotor including an annulus 32. with sets of rotor members 33 and 34 projecting from its opposite end faces. Therotor members of the sets 33 and 34 have a keystone shape as the stator members 18b and 19b and coact therewith. More specifically, the rotor 39 is so positioned With respect to the stators that the rotor members 33 and 34 are mounted to move between the stator members 1812 and 1912 respectively for imparting limited rotative movement to the rotor sleeve 2-8 and the shaft 25 which is keyed thereto. Rotor member 33 has working faces 33a and 33b confronting working faces 18c and il-Sd of different stator members 18b respectively. Rotor member 34 has working faces 34a and 34b confronting working faces 19c and 19d of different stator members 1912 respectively. Each rotor member has on its working faces a vertical groove 35a. An opening 35b extends through the annulus 32 bet-ween each pair of oppositely directed rotor members 33 and 34 in alignment with each groove 35m.

A retaining collar 36 is screw-threaded or otherwise suitably secured in the upper end of the rotor sleeve 28 and encircles the enlarged portion 26 of the stub shaft 25. The collar 36 includes an enlarged portion 37 having an annular groove 38 formed in its inner wall in a position to confront the groove 27 in the enlarged portion 26 of the stub shaft 25. A removable locking ring 39 is confined in the grooves 27 and 38 and retains the fin 24 against axial displacement from the sleeve 28. a

"In assembling the actuator, the stator element '18 is placed in position in sleeve 13, the rotor sleeve -28 with u: the rotor 33 is inserted from the bottom of the stator sleeve '13, and then stator element 119 is placed therein. The stator element 18, rotor sleeve 28 and stator element 19 are held in position by a threaded clamping ring 40 screwed into the threaded course 23. After the rotor is turned through the extreme clockwise and counterclockwise direction to bring both stator elements 18 and 19 in aligned relationship and after the right amount of drag between the stators and the rotor has been set by adjusting nut 40, both stators are pinned and locked in this adjusted position.

Closing the lower end of the sleeve 13 is a cap 41 which is secured in placed by pins 42. The cap 41 has mounted axially thereon a potentiometer 43 (feedback position potentiometer) which is electrically connected to the servo amplifier 56. The shaft 44 of the potentiometer extends into the hollow stub shaft 2-5 and has a screwdriver slot in its end face. The potentiometer shaft 44 is normally locked to turn directly with the rotor sleeve 28 by a clutch 45. This clutch includes a plate 46 secured to the end face of the rotor sleeve 28 by screws 48, a second plate 47, adjustably mounted on the plate 4-6 by screws -2 and a packing such as a grommet 49, surrounding shaft 44 and confined between confronting frusto-conical faces in the plates 46 and 47.

When it is desired to adjust the potentiometer 43, the locking ring 39 is first expanded in the annular groove 38, then the fin 24 and stub shaft may be removed from the rotor sleeve 23. The scnews 52 are then loosened for relieving pressure upon the packing 49. The potentiometer shaft 44 may then be rotated to the desired adjustment, after which the screws 52 can be tightened and the fins and stub shaft returned to the operative position.

To effect the movement or turning motion of the actuator rotor, hydraulic fluid or oil under pressure is supplied from a suitable source (not shown) and returned thereto thnough passageways 66 and 6 1 in the hub 11. The fluid is controlled by the servo valve 55 attached directly to the exterior of the hub. The valve in turn is operated by a servo amplifier 56 in response to a control signal requiring a change in position of the aerodynamic control surfaces or fins. A signal from the potentiometer 43 is continuousuly fed into the servo amplifier 56 to balance out the control signal when the fin has reached the desired position called for by the control signal.

The servo valve directs the fluid under pressure into conduits 62 and 63 to the stator sleeve depending upon the required turning direction. To eflect a counterclockwise movement, conduit 62 is used as the input to the actuator stator sleeve and conduit 63 as the return. Conversely to effect clockwise movement, conduit 63 is used as the input and 62 as the return.

FIG. 4 shows the rotor members 33 halfway between stator members 181). In order to give a complete explanation of the operation of the actuator, the rotor members 33 will be considered to be abutting stator members 1811 adjacent the working face 18c near the entrance of bores 22a, such that the working face 33a of rotor members 33 is contiguous with the working face 180 of stator members 1812. Likewise, the working face 190 of members 1% is contigous with working face 34a of members 34.

The hydraulic fluid flows from the servo valve through conduit 62 to upper groove 15]) on the exterior of stator sleeve 13. The fluid is conveyed around the stator in the upper groove 15]) and then into four bores 22a at the bottom of groove 15b to the inner surface of the stator sleeve adjacent the chamfered edge of a stator working face 180. With the stator and rotor working faces contiguous, the chamfered edge permits the fluid to flow with ease between the contiguous faces. The groove a lets the fluid under pressure be transferred instantaneously through the opening 35b in the annulus 3-2 to the abutting faces 19c and 34a of members 1% and 34-.

With the fluid under pressure introduced between the aligned working faces of both sets of rotor members 33 and 34 and stator members 1812 and 1%, the rotor turns in a counter-clockwise direction. The fluid existing in the space between face 18d of stator member 18a and face 34b of rotor member 34 is ported through opening 35b to the bore 22b, consequently to [lower groove 15b, conduit 63 and then back to the servo valve.

If the control signal calls for movement in the clockwise direction with the rotor in the position of FIG. 4, the fluid is supplied in the reverse manner through conduit 63 to lower groove 15!) to bores 22b and through the stator sleeve. Fluid pressure is exerted against the face 34b of rotor member 34 and also against the face 33b of rotor member 33 after being readily transferred through opening 35b. The rotor then is turned in a clockwise direction with the fluid being ported from the space between face 34a of rotor member 34 and face of stator member (1% by opening 3512, then from the space between the rotor member face 33a and stator member face 18c to the bore 22a to the upper groove 15b and through the conduit 62 back to the servo valve.

It can be readily seen in either turning direction of the rotor that a balanced mechanism is provided by providing for fluid pressure simultaneously at both sides of the annulus 32 and between both sets of rotor and stator members. By having a balanced mechanism in applying the fluid pressure to turn the rotor, a torque is applied to the fin shaft uniformly throughout its length.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. In an aerial vehicle having an exterior body formed with an inwardly projecting hub, the combination of a fin with a hollow stub shaft for attachment to the body, a rotary actuator mounted in said hub, said actuator having a concentric rotor sleeve directly coupled to said stub shaft, a position potentiometer directly connected to said rotary actuator, said potentiometer having a shaft extending into the interior end of said rotor sleeve, and releasable clutch means locking said potentiometer shaft to the interior end of said rotor sleeve, a servo valve mounted on said hub, and means for conveying fluid under pressure from said servo valve to said actuator for imparting a limited turning movement to said sleeve, whereby the potentiometer and fin shafts are turned according to the movement of said sleeve.

2. In an aerial vehicle having an exterior body formed with a hub, the combination of a rotary actuator mounted in said hub, said actuator comprising a stator cylinder secured in said hub, a pair of axially spaced aligned stator elements mounted in said cylinder, a hollow rotor movable within said cylinder between said stator elements, a position potentiometer directly connected to said rotary actuator, said potentiometer mounted axially on the interior end of said cylinder, said potentiometer having a shaft extending axially into said hollow rotor, clutch means for locking said potentiometer shaft to said rotor, said clutch means being releasable through said hollow rotor, whereby said potentiometer shaft can be rotated to a desired adjustment from the outside of said body, a servo valve mounted on said hub and means for conveying fluid from said servo valve to said actuator to impart a limited turning movement to said rotor whereby the potentiometer is turned according to the turning movement of said rotor.

3. A rotary actuator for a fin of an aerial vehicle having an exterior body formed with a hub, said actuator including a cylinder mounted in the hub, a pair of axially spaced aligned stator elements mounted in said cylinder, a hollow rotor sleeve for securing a fin stub shaft, said sleeve having centrally formed from its ends a circumferential annulus, said sleeve being placed within said cylinder with the annulus between the spaced stator elements, said annulus having axially projecting rotor members cooperating with said stator elements, and means for introducing fluid between the rotor members and the stator elements for imparting limited turning movement to the rotor sleeve whereby the stub shaft is turned according to the movement of the rotor sleeve.

4. In combination with an aerial vehicle having an exterior body formed with an inwardly projecting hub, and a fin with a hollow stub shaft for attachment to the hub; a rotary actuator directly secured in said stub shaft, said actuator including a cylinder mounted in the hub, a pair of axially spaced aligned stator elements mounted in said cylinder, a hollow rotor within said cylinder between said stator elements encircling said fin stub shaft and being keyed thereto, and a potentiometer mounted axially on the lower end of said cylinder, said potentiometer having a shaft extending into the interior end of the fin hollow stub shaft, clutch means for locking the potentiometer shaft to said rotor, means for introducing fluid to said rotor for imparting a limited turning movement to said rotor whereby the fin and the potentiometer shafts are turned according to the movement of the rotor.

5. A rotary actuator for imparting limited movement to a fin of an aerial vehicle, said actuator comprising a cylinder having circumferential grooves in its outer wall, a pair of axially spaced aligned stators mounted in said cylinder, each of said stators having a plurality of axially projecting stator members, a hollow rotor sleeve for encircling a shaft of a fin, said sleeve having centrally formed on its outer wall an annulus, said sleeve being placed within said cylinder with the annulus between the spaced stators, said annulus having oppositely directed aligned rotor members being meshed with said stator members, said annulus having an opening extending axially therethrough in alignment with the working faces of the oppositely directed rotor members, said cylinder having a plurality of bores from said grooves to the working faces of said stator elements, whereby hydraulic fluid supplied to cylinder grooves is conveyed through the bores in the annulus opening so that the fluid is introduced at both sides of the annulus between the working faces of said rotor and stator members providing limited movement to the rotor sleeve.

6. A rotary actuator for imparting limited movement to a fin of an aerial vehicle, said actuator comprising a cylinder having circumferential grooves in its outer wall, upper and lower stator rings axially spaced apart in said cylinder, each of said stator rings having a plurality of axially projecting stator members, said stator members of the upper ring being downwardly directed, said stator member of the lower ring being upwardly directed, said upper and lower projecting stator members being aligned, said stator members having working faces; a hollow rotor sleeve being movable within said cylinder for encircling a shaft of a fin, said sleeve having a circumferential annulus, said annulus having oppositely directed aligned sets of rotor members, said sleeve annulus being placed between said upper and lower stator members and said sets of rotor members being meshed respectively with said upper and lower stator members, said rotor members having working faces in opposition to working faces of said stator members, said rotor members having on each working face an axially directed groove, said annulus having an opening extending axially therethrough in alignment with the grooves on the aligned working faces of the oppositely directed rotor members, said cylinder having a plurality of bores extending from said circumferential grooves to the working faces of said upper and lower stator members, whereby hydraulic fluid being supplied under pressure to the cylinder grooves is conveyed through the cylinder bores to working faces of one set of rotor and stator members and is introduced approximately simultaneously by the directed groove through the annulus opening to working faces of another set of rotor and stator members providing limited balanced movement to the rotor sleeve.

References tCited in the file of this patent UNITED STATES PATENTS 2,778,338 Shafer M Jan. 22,1957 2,811,834 Shafer et a1 Nov. 5, 1957 2,851,982 Fogarty Sept. 16, 1958 2,870,748 Hemphill Jan. 27, 1959 2,911,956 Smith Nov. 10, 1959 2,972,456 Ransom et a1. Feb. 21, 1961 2,996,267 Warren Aug. 15, 1961 FOREIGN PATENTS 899,159 Germany July 8, 1949 

1. IN AN AERIAL VEHICLE HAVING AN EXTERIOR BODY FORMED WITH AN INWARDLY PROJECTING HUB, THE COMBINATION OF A FIN WITH A HOLLOW STUB SHAFT FOR ATTACHMENT TO THE BODY, A ROTARY ACTUATOR MOUNTED IN SAID HUB, SAID ACTUATOR HAVING A CONCENTRIC ROTOR SLEEVE DIRECTLY COUPLED TO SAID STUB SHAFT, A POSITION POTENTIOMETER DIRECTLY CONNECTED TO SAID ROTARY ACTUATOR, SAID POTENTIOMETER HAVING A SHAFT EXTENDING INTO THE INTERIOR END OF SAID ROTOR SLEEVE, AND RELEASABLE CLUTCH MEANS LOCKING SAID POTENTIOMETER SHAFT TO THE INTERIOR END OF SAID ROTOR SLEEVE, A SERVO VALVE MOUNTED ON SAID HUB, AND MEANS FOR CONVEYING FLUID UNDER PRESSURE FROM SAID SERVO VALVE TO SAID ACTUATOR FOR IMPARTING A LIMITED TURNING MOVEMENT TO SAID SLEEVE, WHEREBY THE POTENTIOMETER AND FIN SHAFTS ARE TURNED ACCORDING TO THE MOVEMENT OF SAID SLEEVE. 